Control method and device of low-pressure EGR system, vehicle and storage medium

Abstract

The invention relates to a control method and device for a low-pressure EGR system, a vehicle and a storage medium, and the method comprises the steps that gas parameters of at least one preset gas detection point of the low-pressure EGR system of the vehicle are obtained, and the liquid water amount of the low-pressure EGR system is calculated based on the gas parameters; current driving parameters of the vehicle are obtained, and the engine working condition of the vehicle is determined based on the current driving parameters and the gas parameters; based on the liquid water volume and the engine working condition, whether the vehicle meets the preset combustion stability condition or not is judged, under the condition that the vehicle does not meet the combustion stability condition, the target opening degree of an EGR valve in the low-pressure EGR system is determined based on the liquid water volume and the engine working condition, and the EGR valve is controlled to be opened to the target opening degree so as to meet the combustion stability condition. Therefore, the technical problems that in the related technology, due to the fact that condensate water is consumed or separated by arranging an additional device, the cost is high, additional space design needs to be conducted on the interior of the vehicle, and certain potential safety hazards exist are solved.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to a control method, device, vehicle and storage medium for a low-pressure EGR system. Background Art

[0002] In order to improve the thermal efficiency of the engine, the compression ratio of the engine needs to be increased. At present, the compression ratio of engines with a thermal efficiency of more than 40% is basically above 13. The tendency of engine knock increases under high compression ratio, and the combustion phase delay caused by knock limits the further improvement of thermal efficiency. To deal with this phenomenon, EGR (Exhaust Gas Recirculation) is a commonly used measure. By introducing EGR, the engine combustion efficiency can be improved, the pumping loss can be reduced, the heat transfer loss can be reduced, and the combustion phase can be improved. Under the combined effect, the engine thermal efficiency can be improved by more than 2%.

[0003] In order to further reduce fuel consumption, the engine will use a low-pressure EGR system. The condensed water problem caused by low-pressure EGR technology is a major factor affecting the application of this technology and engine reliability. Since EGR usually has very high temperature and humidity, when high-temperature EGR and low-temperature fresh air are mixed and then supercharged and intercooled, the temperature of the mixture decreases and condensed water may be generated. This condensed water enters the cylinder and causes poor combustion stability or even misfire.

[0004] In the related art, condensed water can be consumed or separated by setting up additional devices, but the cost is high and additional space design is required inside the vehicle, which poses certain safety hazards and needs to be improved. Summary of the invention

[0005] The present application provides a control method, device, vehicle and storage medium for a low-pressure EGR system to solve the technical problems in the related art that the consumption or separation of condensed water by setting up additional devices is costly, requires additional space design inside the vehicle, and poses certain safety hazards.

[0006] The first aspect of the present application provides a control method for a low-pressure EGR system, comprising the following steps: obtaining gas parameters of at least one preset gas detection point of a low-pressure EGR system of a vehicle, and calculating the liquid water volume of the low-pressure EGR system based on the gas parameters; obtaining current driving parameters of the vehicle, and determining the engine operating conditions of the vehicle based on the current driving parameters and the gas parameters; judging whether the vehicle meets preset combustion stability conditions based on the liquid water volume and the engine operating conditions, and if the vehicle does not meet the combustion stability conditions, determining a target opening of an EGR valve in the low-pressure EGR system based on the liquid water volume and the engine operating conditions, and controlling the EGR valve to open to the target opening to meet the combustion stability conditions.

[0007] Optionally, in one embodiment of the present application, the gas parameters of at least one preset gas detection point of the low-pressure EGR system of the vehicle are obtained, and the liquid water content of the low-pressure EGR system is calculated based on the gas parameters, including: collecting fresh air parameters of a first preset gas detection point, and calculating a first water content in the fresh air based on the fresh air parameters, wherein the first preset gas detection point is arranged on the intake manifold of the low-pressure EGR system; collecting EGR gas parameters of a second preset gas detection point, and calculating a second water content in the EGR based on the EGR gas parameters, wherein the second preset gas detection point is arranged on the EGR pipe in front of the EGR valve; collecting intercooler outlet gas parameters of a third preset gas detection point, and calculating the saturated water content at the intercooler outlet based on the intercooler outlet gas parameters, wherein the third preset gas detection point is arranged after the intercooler; calculating the liquid water content based on the first water content, the second water content and the saturated water content.

[0008] Optionally, in one embodiment of the present application, determining the engine operating condition of the vehicle based on the current driving parameters and the gas parameters includes: obtaining the engine speed of the vehicle based on the current driving parameters; and obtaining the engine operating condition by combining the engine speed and the gas mass flow rate in the fresh air parameters.

[0009] Optionally, in one embodiment of the present application, judging whether the vehicle meets the preset combustion stability condition based on the liquid water volume and the engine operating condition includes: matching the maximum tolerable liquid water volume under the engine operating condition using a preset operating condition-water volume comparison table; judging whether the liquid water volume is less than or equal to the maximum tolerable liquid water volume; if the liquid water volume is less than or equal to the maximum tolerable liquid water volume, judging that the vehicle meets the preset combustion stability condition, otherwise, judging that the vehicle does not meet the preset combustion stability condition.

[0010] Optionally, in one embodiment of the present application, it also includes: recording the number of adjustments of the EGR valve; when the number of adjustments reaches a preset number, based on the corresponding gas parameters, liquid water volume and engine operating conditions during each adjustment, generating a corresponding low-pressure EGR system historical control message, and sending the low-pressure EGR system historical control message to a preset terminal.

[0011] The second aspect of the present application provides a control device for a low-pressure EGR system, including: a first acquisition module, used to acquire gas parameters of at least one preset gas detection point of the low-pressure EGR system of a vehicle, and calculate the liquid water volume of the low-pressure EGR system based on the gas parameters; a second acquisition module, used to acquire current driving parameters of the vehicle, and determine the engine operating conditions of the vehicle based on the current driving parameters and the gas parameters; a control module, used to determine whether the vehicle meets preset combustion stability conditions based on the liquid water volume and the engine operating conditions, and if the vehicle does not meet the combustion stability conditions, determine the target opening of the EGR valve in the low-pressure EGR system based on the liquid water volume and the engine operating conditions, and control the EGR valve to open to the target opening to meet the combustion stability conditions.

[0012] Optionally, in one embodiment of the present application, the first acquisition module includes: a first acquisition unit, used to collect fresh air parameters of a first preset gas detection point, and calculate a first water content in the fresh air based on the fresh air parameters, wherein the first preset gas detection point is set on the intake manifold of the low-pressure EGR system; a second acquisition unit, used to collect EGR gas parameters of a second preset gas detection point, and calculate a second water content in the EGR based on the EGR gas parameters, wherein the second preset gas detection point is set on the EGR pipe in front of the EGR valve; a third acquisition unit, used to collect intercooler outlet gas parameters of a third preset gas detection point, and calculate the saturated water content at the intercooler outlet based on the intercooler outlet gas parameters, wherein the third preset gas detection point is set after the intercooler; a calculation unit, used to calculate the liquid water amount based on the first water content, the second water content and the saturated water content.

[0013] Optionally, in one embodiment of the present application, the second acquisition module includes: a first acquisition unit, used to obtain the engine speed of the vehicle based on the current driving parameters; and a second acquisition unit, used to obtain the engine operating condition by combining the engine speed and the gas mass flow rate in the fresh air parameters.

[0014] Optionally, in one embodiment of the present application, the control module includes: a matching unit, used to match the maximum tolerable liquid water volume under the engine operating condition using a preset operating condition-water volume comparison table; a judgment unit, used to judge whether the liquid water volume is less than or equal to the maximum tolerable liquid water volume; a judgment unit, used to judge that the vehicle meets the preset combustion stability condition when the liquid water volume is less than or equal to the maximum tolerable liquid water volume, otherwise, judge that the vehicle does not meet the preset combustion stability condition.

[0015] Optionally, in one embodiment of the present application, it also includes: a recording module for recording the number of adjustments of the EGR valve; a generation module for generating a corresponding low-pressure EGR system historical control message based on the corresponding gas parameters, liquid water volume and engine operating conditions at each adjustment when the number of adjustments reaches a preset number, and sending the low-pressure EGR system historical control message to a preset terminal.

[0016] A third aspect of the present application provides a vehicle, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method of the low-pressure EGR system as described in the above embodiment.

[0017] A fourth aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the control method of the low-pressure EGR system as described in the above embodiment.

[0018] A fifth aspect of the present application provides a computer program product, including a computer program, which, when executed, is used to implement the control method of the low-pressure EGR system as described above.

[0019] The embodiment of the present application can detect the corresponding gas parameters from at least one preset gas detection point of the low-pressure EGR system of the vehicle, and calculate the liquid water volume of the low-pressure EGR system according to the gas parameters of each preset gas detection point, and judge whether the vehicle meets the preset combustion stability conditions according to the liquid water volume and the engine operating conditions, so that when the vehicle does not meet the combustion stability conditions, the opening of the EGR valve in the low-pressure EGR system is adjusted based on the liquid water volume and the engine operating conditions, so that the vehicle meets the combustion stability conditions, and without adding additional costs, by calculating the precipitation of condensed water after supercharging and intercooling, and comparing it with the calibrated maximum allowable water volume, the EGR valve is adjusted to achieve stable combustion and improve the safety of the vehicle. Therefore, the technical problem in the related art that the consumption or separation of condensed water by setting additional devices is high in cost, and additional space design is required inside the vehicle, which has certain safety hazards is solved.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] Figure 1 is a structural schematic diagram of a low-pressure EGR system according to an embodiment of the present application;

[0023] Figure 2 A flow chart of a control method of a low-pressure EGR system provided according to an embodiment of the present application;

[0024] Figure 3 This is a schematic diagram of the principle of a control method for a low-pressure EGR system according to an embodiment of the present application;

[0025] Figure 4 A schematic diagram of the structure of a control device for a low-pressure EGR system provided according to an embodiment of the present application;

[0026] Figure 5 It is a schematic diagram of the structure of a vehicle provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0028] The following describes the control method, device, vehicle and storage medium of the low-pressure EGR system of the embodiment of the present application with reference to the accompanying drawings. In view of the technical problem that the consumption or separation of condensed water by setting an additional device in the related art mentioned in the background technology is costly and requires additional space design inside the vehicle, which has certain safety hazards, the present application provides a control method of a low-pressure EGR system, in which the corresponding gas parameters can be detected from at least one preset gas detection point of the low-pressure EGR system of the vehicle, and the liquid water volume of the low-pressure EGR system is calculated according to the gas parameters of each preset gas detection point, and the vehicle satisfies the preset combustion stability condition according to the liquid water volume and the engine operating condition, so that when the vehicle does not meet the combustion stability condition, the opening of the EGR valve in the low-pressure EGR system is adjusted based on the liquid water volume and the engine operating condition, so that the vehicle meets the combustion stability condition, and the condensed water precipitation after supercharging and intercooling is calculated without increasing additional costs, and compared with the calibrated maximum allowable water volume, the EGR valve is adjusted to achieve stable combustion and improve the safety of the vehicle. Thereby, the technical problem in the related art that the consumption or separation of condensed water requires additional devices, which is costly, requires additional space design inside the vehicle, and poses certain safety hazards is solved.

[0029] Before explaining the control method of the low-pressure EGR system according to the embodiment of the present application, the structure involved in the embodiment of the present application is first described.

[0030] like Figure 1 As shown, the low-pressure EGR system involved in the embodiment of the present application includes: an engine body 1, an intake manifold 2, an intake manifold 3, an exhaust manifold 4, an exhaust manifold 5, an air filter 6, a mixer 7, a compressor 8, an intercooler 9, a throttle 10, a turbine 11, a three-way catalytic converter 12, a particulate filter 13, an EGR pipe 14, an EGR cooler 15, an EGR valve 16, an EGR temperature sensor 17, an EGR flow sensor 18, an air humidity sensor 19, an air temperature sensor 20, an air flow sensor 21, a controller 22, a temperature sensor 23 and a speed sensor 24.

[0031] The engine intake manifold 2 is connected to the intake manifold 3 through a throttle valve 10. The intake manifold 3 is provided with an air filter 6, a mixer 7, a compressor 8, and an intercooler 9 in sequence. The exhaust manifold 5 is provided with a turbine 11, a three-way catalytic converter 12, and a particulate collector 13 in sequence. The compressor 8 and the turbine 9 are connected by a shaft to form a supercharger. The intake manifold 3 and the exhaust manifold 5 are connected through an EGR pipe 14. The EGR pipe 14 is provided with an EGR cooler 15 and an EGR valve 16.

[0032] When the engine is working, fresh air from the outside enters the mixer 7 through the air filter 6, and the exhaust gas generated by the engine body 1 is discharged into the outside air through the exhaust manifold 4, the exhaust header 5, the turbine 11, the three-way catalytic converter 12, and the particulate collector 13 in sequence. Part of the exhaust gas enters the mixer 7 after the three-way catalytic converter 12 through the EGR pipe 14, the EGR intercooler 15, and the EGR valve 16, and mixes with the fresh air. This part of the gas is called recirculated exhaust gas (EGR). The mixed gas enters the engine body 1 through the compressor 8, the intercooler 9, the intake header 3, and the intake manifold 2. Through the above-mentioned intake, exhaust, and exhaust gas recirculation, a complete engine working process is formed.

[0033] An air humidity sensor 19, an air temperature sensor 20, and an air flow sensor 21 are installed on the intake manifold 3 after the air filter 6 to monitor the humidity of the fresh air. Temperature T air , mass flow rate m air On the EGR pipe 14 in front of the EGR valve 16, an EGR temperature sensor 17 and an EGR flow sensor 18 are installed to monitor the temperature T of the EGR. EGR , mass flow rate m EGR .

[0034] A temperature sensor 23 is installed after the intercooler 9 to monitor the temperature of the mixed gas after the intercooler. A speed sensor 24 is installed on the engine 1 to monitor the engine speed.

[0035] The low-pressure EGR system further includes a controller 22 for acquiring sensor data, performing calculations and issuing commands.

[0036] Specifically, Figure 2 A flow chart of a control method for a low-pressure EGR system provided in an embodiment of the present application.

[0037] like Figure 2 As shown, the control method of the low-pressure EGR system includes the following steps:

[0038] In step S201, gas parameters of at least one preset gas detection point of a low-pressure EGR system of a vehicle are obtained, and the amount of liquid water in the low-pressure EGR system is calculated based on the gas parameters.

[0039] During the actual implementation process, the embodiment of the present application can set multiple gas detection points in the low-pressure EGR system to detect the gas state of each gas detection point, and then evaluate the water content of each gas detection point, so as to comprehensively measure the water content of each gas detection point and obtain the liquid water content of the low-pressure EGR system.

[0040] The gas parameters may include gas temperature, mass flow, gas quality, etc. Each gas detection point may be provided with a sensor for detecting gas parameters, such as a flow sensor, a temperature sensor, etc.

[0041] Optionally, in one embodiment of the present application, gas parameters of at least one preset gas detection point of a low-pressure EGR system of a vehicle are obtained, and the liquid water content of the low-pressure EGR system is calculated based on the gas parameters, including: collecting fresh air parameters of a first preset gas detection point, and calculating a first water content in the fresh air based on the fresh air parameters, wherein the first preset gas detection point is set on an intake manifold of the low-pressure EGR system; collecting EGR gas parameters of a second preset gas detection point, and calculating a second water content in the EGR based on the EGR gas parameters, wherein the second preset gas detection point is set on the EGR pipe in front of the EGR valve; collecting intercooler outlet gas parameters of a third preset gas detection point, and calculating the saturated water content at the intercooler outlet based on the intercooler outlet gas parameters, wherein the third preset gas detection point is set after the intercooler; and calculating the liquid water content based on the first water content, the second water content and the saturated water content.

[0042] It is understandable that the intercooler can be used to cool the boost air of an internal combustion engine. When the engine uses a supercharger to compress the incoming air, the air temperature will increase, thereby reducing the efficiency of the engine and may cause problems such as knock. The role of the intercooler is to reduce the temperature of the compressed air, thereby increasing its density, so that more oxygen can enter the engine, allowing more fuel injection, and ultimately increasing the engine's power output and efficiency.

[0043] From this we can see that as the temperature of the gas passing through the intercooler drops, the amount of moisture that the air can carry decreases. If the moisture content in the intake air exceeds the new saturation point, moisture will condense, which is not conducive to engine operation.

[0044] Therefore, in the embodiment of the present application, a gas detection point is set at the outlet of the intercooler to determine the saturated water content at the outlet of the intercooler, so as to obtain a more accurate liquid water amount of the low-pressure EGR system.

[0045] As a possible way to achieve this, Figure 1 As shown, the embodiment of the present application can obtain the humidity of fresh air through the air humidity sensor 19, the air temperature sensor 20, and the air flow sensor 21 at the first preset gas detection point when the vehicle is started and driving normally. Temperature T air , mass flow rate m air And other parameters, according to the humid air state parameter equation, calculate the water content m1 in the fresh air.

[0046] The EGR temperature T is obtained by the EGR temperature sensor 17 and the EGR flow sensor 18 at the second preset gas detection point. EGR , Gas humidity Mass flow rate m EGR And other parameters, according to the fuel combustion chemical reaction equation, calculate the water content m2 in EGR.

[0047] The water content m3 in the mixed gas at the outlet of the intercooler 9 is calculated, wherein m3=m1+m2.

[0048] The mixed gas temperature T at the outlet of the intercooler 9 is obtained by the intercooler post temperature sensor 23 at the third preset gas detection point. mix , calculate the intercooler outlet gas mass m mix , where m mix =m air +m EGR , according to the humid air state parameter equation, calculate the saturated water content m4 in the mixed gas.

[0049] Calculate the amount of liquid water m5 condensed, where m5 = m3 - m4.

[0050] In step S202, the current driving parameters of the vehicle are acquired, and the engine operating conditions of the vehicle are determined based on the current driving parameters and gas parameters.

[0051] Furthermore, the embodiment of the present application can obtain the current driving parameters of the vehicle, such as the engine speed, etc., so as to obtain the engine operating condition according to the current driving parameters and gas parameters, such as the gas mass flow rate.

[0052] Optionally, in one embodiment of the present application, the engine operating condition of the vehicle is determined based on the current driving parameters and gas parameters, including: obtaining the engine speed of the vehicle based on the current driving parameters; and obtaining the engine operating condition by combining the engine speed and the gas mass flow rate in the fresh air parameters.

[0053] It can be understood that the engine speed is a parameter that can directly reflect the operating state of the engine.

[0054] Under idle conditions, the engine runs at the minimum stable speed, which is used when the vehicle is stopped but the engine keeps running.

[0055] Under partial load conditions, the engine is at a medium speed and is used when the vehicle is traveling at a constant speed or accelerating slightly.

[0056] Under full load conditions, the engine will reach a higher speed, which is used in conditions that require maximum power output, such as rapid acceleration or climbing.

[0057] The main function of the low-pressure EGR system is to reintroduce part of the exhaust gas into the intake manifold, mix it with fresh air and then re-enter the cylinder for combustion, thereby reducing the emission of nitrogen oxides (NOx). The change in the gas mass flow rate of the low-pressure EGR system, such as the change in the gas mass flow rate of fresh air, can reflect the needs of the engine under different working conditions.

[0058] At idle and low load conditions, the gas mass flow rate is usually small because there is no need to reduce NOx emissions much.

[0059] When the engine is in medium load condition, the gas mass flow rate will gradually increase to meet the needs of emission control.

[0060] Under high load conditions, the gas mass flow may be reduced or shut off because the engine requires more fresh air to ensure combustion efficiency and to prevent performance degradation and possible excessive heat load.

[0061] In summary, in the embodiments of the present application, when the engine speed is low and the gas mass flow rate is small, the engine may be in an idle or light-load condition.

[0062] An increase in speed with a moderate increase in gas mass flow indicates that the engine is accelerating or is operating at part load.

[0063] When the speed is high but the gas mass flow is reduced or even shut off, the engine may be under high load or full load conditions.

[0064] In addition, the embodiments of the present application may also be combined with other sensor data, such as throttle position, intake temperature, intake pressure, etc. for comprehensive analysis to obtain more accurate engine operating conditions.

[0065] In step S203, based on the liquid water amount and the engine operating condition, it is determined whether the vehicle meets the preset combustion stability conditions. If the vehicle does not meet the combustion stability conditions, the target opening of the EGR valve in the low-pressure EGR system is determined based on the liquid water amount and the engine operating condition, and the EGR valve is controlled to open to the target opening to meet the combustion stability conditions.

[0066] It is understandable that adjusting the EGR valve can affect the performance and emissions of the engine. Adjusting the EGR valve opening can optimize the NOx emission level under different operating conditions; adjusting the EGR valve opening can improve fuel economy; adjusting the EGR valve opening can balance the relationship between emission control and engine performance, etc.

[0067] Among them, the increase in the opening of the EGR valve means that more exhaust gas is reintroduced into the intake manifold, diluting the fresh air entering the cylinder, thereby reducing the concentration of oxygen in the cylinder and reducing the generation of carbon oxides, thereby reducing the combustion temperature and increasing the EGR rate, making the combustion process unstable.

[0068] The reduced opening of the EGR valve means that less exhaust gas is introduced into the intake manifold, the proportion of fresh air increases relatively, and the oxygen concentration also increases accordingly, which is beneficial to improving combustion efficiency and engine power output. The combustion process is more intense and the combustion temperature will increase accordingly, making the combustion process more stable.

[0069] In some embodiments, based on the liquid water volume and engine operating conditions, the embodiments of the present application can determine whether the engine has the hidden danger of unstable combustion, that is, whether the engine can burn stably under the current engine operating conditions and the current liquid water volume, and if stable combustion is not possible, adjust the EGR valve opening to increase combustion stability.

[0070] Optionally, in one embodiment of the present application, based on the liquid water volume and the engine operating condition, it is determined whether the vehicle meets the preset combustion stability conditions, including: using a preset operating condition-water volume comparison table to match the maximum tolerable liquid water volume under the engine operating condition; determining whether the liquid water volume is less than or equal to the maximum tolerable liquid water volume; if the liquid water volume is less than or equal to the maximum tolerable liquid water volume, it is determined that the vehicle meets the preset combustion stability conditions, otherwise, it is determined that the vehicle does not meet the preset combustion stability conditions.

[0071] For example, the embodiment of the present application can use a preset operating condition-water volume comparison table to match the engine operating condition to obtain the maximum tolerable liquid water volume m6 of the engine operating condition, and then compare the relationship between m5 and m6. If m5≤m6, stable combustion is achieved; otherwise, unstable combustion or even misfire may occur. At this time, the EGR valve opening is reduced until m5≤m6 is established.

[0072] It should be noted that the preset operating condition-water volume comparison table can be generated using big data, or obtained by collecting actual parameters of vehicles of the same model, and no specific restrictions are made here.

[0073] Optionally, in one embodiment of the present application, it also includes: recording the number of adjustments of the EGR valve; when the number of adjustments reaches a preset number, based on the corresponding gas parameters, liquid water volume and engine operating conditions during each adjustment, generating a corresponding low-pressure EGR system historical control message, and sending the low-pressure EGR system historical control message to a preset terminal.

[0074] In the actual implementation process, the embodiment of the present application can also record the number of times the EGR valve is adjusted, that is, the number of times the EGR valve is adjusted due to a high liquid water volume. When the number of adjustments reaches a certain value, it indicates that the low-pressure EGR system of the vehicle may have a fault, such as a sensor fault, etc., which makes the calculated liquid water volume high. At this time, the embodiment of the present application can integrate the gas parameters of each gas detection point corresponding to each adjustment, the calculated liquid water volume and the engine operating conditions, and generate a low-pressure EGR system historical control message, and send the low-pressure EGR system historical control message to a preset terminal, such as a maintenance terminal, a user terminal, a car company terminal, etc.

[0075] For example, after the automobile manufacturer's terminal receives the historical control message of the low-pressure EGR system, it can comprehensively determine the vehicle's problems and make subsequent improvements to the vehicle structure or parts; after the maintenance terminal receives the historical control message of the low-pressure EGR system, it can perform fault diagnosis in advance to speed up the maintenance process.

[0076] Combination Figure 1 and Figure 3 As shown, the working principle of the control method of the low-pressure EGR system of the embodiment of the present application is described in detail with an embodiment.

[0077] like Figure 1 , which is a schematic structural diagram of a low-pressure EGR system according to an embodiment of the present application;

[0078] like Figure 3 As shown, the working principle of the control method of the low-pressure EGR system of an embodiment of the present application.

[0079] In the actual implementation process, the embodiment of the present application can obtain the humidity of fresh air through the air humidity sensor 19, the air temperature sensor 20, and the air flow sensor 21 when the vehicle is started and driving normally. Temperature T air , mass flow rate m air And other parameters, according to the humid air state parameter equation, calculate the water content m1 in the fresh air.

[0080] The EGR temperature T is obtained by the EGR temperature sensor 17 and the EGR flow sensor 18. EGR , Gas humidity Mass flow rate m EGR And other parameters, according to the fuel combustion chemical reaction equation, calculate the water content m2 in EGR.

[0081] The water content m3 in the mixed gas at the outlet of the intercooler 9 is calculated, wherein m3=m1+m2.

[0082] The mixed gas temperature T at the outlet of the intercooler 9 is obtained by the temperature sensor 23 after the intercooler 9.mix , calculate the intercooler outlet gas mass m mix , where m mix =m air +m EGR , according to the humid air state parameter equation, calculate the saturated water content m4 in the mixed gas.

[0083] Calculate the amount of liquid water m5 condensed, where m5 = m3 - m4.

[0084] The engine speed n and gas mass flow m are monitored by the speed sensor 24 and the air flow sensor 21. air The engine operating condition is determined by the controller 22, and the maximum tolerable liquid water volume m6 under the current operating condition is obtained by looking up the table through the built-in MAP of the controller 22.

[0085] Compare the relationship between m5 and m6. If m5≤m6, stable combustion is achieved; otherwise, unstable combustion or even misfire may occur. At this time, reduce the EGR valve opening until m5≤m6 is established.

[0086] According to the control method of the low-pressure EGR system proposed in the embodiment of the present application, the corresponding gas parameters can be detected from at least one preset gas detection point of the low-pressure EGR system of the vehicle, and the liquid water volume of the low-pressure EGR system can be calculated according to the gas parameters of each preset gas detection point, and the vehicle can be judged whether it meets the preset combustion stability conditions according to the liquid water volume and the engine operating conditions, so that when the vehicle does not meet the combustion stability conditions, the opening of the EGR valve in the low-pressure EGR system is adjusted based on the liquid water volume and the engine operating conditions, so that the vehicle meets the combustion stability conditions, and without adding additional costs, the condensed water precipitation after supercharging and intercooling is calculated and compared with the calibrated maximum allowable water volume, and the EGR valve is adjusted to achieve stable combustion and improve the safety of the vehicle. Therefore, the technical problem in the related art that the consumption or separation of condensed water by setting additional devices is high in cost, and additional space design is required inside the vehicle, which has certain safety hazards is solved.

[0087] Next, a control device for a low-pressure EGR system according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0088] Figure 4 It is a block diagram of a control device of a low-pressure EGR system according to an embodiment of the present application.

[0089] like Figure 4 As shown, the control device 40 of the low-pressure EGR system includes: a first acquisition module 100 , a second acquisition module 200 and a control module 300 .

[0090] Specifically, the first acquisition module 100 is used to acquire gas parameters of at least one preset gas detection point of the low-pressure EGR system of the vehicle, and calculate the liquid water amount of the low-pressure EGR system based on the gas parameters.

[0091] The second acquisition module 200 is used to acquire the current driving parameters of the vehicle and determine the engine operating condition of the vehicle based on the current driving parameters and gas parameters.

[0092] The control module 300 is used to determine whether the vehicle meets the preset combustion stability conditions based on the liquid water amount and the engine operating conditions, and when the vehicle does not meet the combustion stability conditions, determine the target opening of the EGR valve in the low-pressure EGR system based on the liquid water amount and the engine operating conditions, and control the EGR valve to open to the target opening to meet the combustion stability conditions.

[0093] Optionally, in one embodiment of the present application, the first acquisition module 100 includes: a first acquisition unit, a second acquisition unit, a third acquisition unit and a calculation unit.

[0094] Among them, the first collection unit is used to collect fresh air parameters of a first preset gas detection point, and calculate the first water content in the fresh air based on the fresh air parameters, wherein the first preset gas detection point is set on the intake manifold of the low-pressure EGR system.

[0095] The second collection unit is used to collect EGR gas parameters of a second preset gas detection point and calculate a second water content in the EGR based on the EGR gas parameters, wherein the second preset gas detection point is set on the EGR pipe before the EGR valve.

[0096] The third collection unit is used to collect the gas parameters of the intercooler outlet at the third preset gas detection point, and calculate the saturated water content at the intercooler outlet based on the gas parameters of the intercooler outlet, wherein the third preset gas detection point is set after the intercooler.

[0097] A calculation unit is used to calculate the liquid water content based on the first water content, the second water content and the saturated water content.

[0098] Optionally, in one embodiment of the present application, the second acquisition module 200 includes: a first acquisition unit and a second acquisition unit.

[0099] Wherein, the first acquisition unit is used to obtain the engine speed of the vehicle based on the current driving parameters.

[0100] The second acquisition unit is used to obtain the engine operating condition by combining the engine speed and the gas mass flow rate in the fresh air parameter.

[0101] Optionally, in one embodiment of the present application, the control module 300 includes: a matching unit, a judging unit and a determining unit.

[0102] Among them, the matching unit is used to match the maximum tolerable liquid water volume under the engine working condition using a preset working condition-water volume comparison table.

[0103] The judging unit is used to judge whether the liquid volume is less than or equal to the maximum tolerable liquid volume.

[0104] The determination unit is used to determine that the vehicle meets the preset combustion stability condition when the liquid water amount is less than or equal to the maximum tolerable liquid water amount, otherwise, determine that the vehicle does not meet the preset combustion stability condition.

[0105] Optionally, in one embodiment of the present application, the control device 40 of the low-pressure EGR system further includes: a recording module and a generating module.

[0106] Among them, the recording module is used to record the number of times the EGR valve is adjusted.

[0107] The generation module is used to generate a corresponding low-pressure EGR system historical control message based on the corresponding gas parameters, liquid water volume and engine operating conditions during each adjustment when the number of adjustments reaches a preset number, and send the low-pressure EGR system historical control message to a preset terminal.

[0108] It should be noted that the aforementioned explanation of the embodiment of the control method of the low-pressure EGR system is also applicable to the control device of the low-pressure EGR system of this embodiment, and will not be repeated here.

[0109] According to the control device of the low-pressure EGR system proposed in the embodiment of the present application, the corresponding gas parameters can be detected from at least one preset gas detection point of the low-pressure EGR system of the vehicle, and the liquid water volume of the low-pressure EGR system can be calculated according to the gas parameters of each preset gas detection point, and the vehicle can be judged whether it meets the preset combustion stability conditions according to the liquid water volume and the engine operating conditions, so that when the vehicle does not meet the combustion stability conditions, the opening of the EGR valve in the low-pressure EGR system is adjusted based on the liquid water volume and the engine operating conditions, so that the vehicle meets the combustion stability conditions, and without adding additional costs, the condensed water precipitation after supercharging and intercooling is calculated and compared with the calibrated maximum allowable water volume, and the EGR valve is adjusted to achieve stable combustion and improve the safety of the vehicle. Therefore, the technical problem in the related art that the consumption or separation of condensed water by setting additional devices is high in cost, and additional space design is required inside the vehicle, which has certain safety hazards is solved.

[0110] Figure 5 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. The vehicle may include:

[0111] A memory 501 , a processor 502 , and a computer program stored in the memory 501 and executable on the processor 502 .

[0112] When the processor 502 executes the program, the control method of the low-pressure EGR system provided in the above embodiment is implemented.

[0113] Furthermore, the vehicle also includes:

[0114] The communication interface 503 is used for communication between the memory 501 and the processor 502 .

[0115] The memory 501 is used to store computer programs that can be executed on the processor 502 .

[0116] The memory 501 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0117] If the memory 501, the processor 502 and the communication interface 503 are implemented independently, the communication interface 503, the memory 501 and the processor 502 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0118] Optionally, in a specific implementation, if the memory 501, the processor 502 and the communication interface 503 are integrated on a chip, the memory 501, the processor 502 and the communication interface 503 can communicate with each other through an internal interface.

[0119] The processor 502 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0120] This embodiment also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the control method of the low-pressure EGR system as described above is implemented.

[0121] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the control method of the low-pressure EGR system provided by an embodiment of the present invention.

[0122] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0123] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0124] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0125] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0126] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0127] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0128] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0129] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A control method for a low-pressure EGR system, characterized in that: The following steps are involved: Acquire gas parameters of at least one preset gas detection point of a low-pressure EGR system of a vehicle, and calculate the liquid water volume of the low-pressure EGR system based on the gas parameters; Acquiring current driving parameters of the vehicle, and determining an engine operating condition of the vehicle based on the current driving parameters and the gas parameters; Based on the liquid water amount and the engine operating condition, it is determined whether the vehicle satisfies a preset combustion stability condition, and if the vehicle does not satisfy the combustion stability condition, a target opening of an EGR valve in the low-pressure EGR system is determined based on the liquid water amount and the engine operating condition, and the EGR valve is controlled to open to the target opening to satisfy the combustion stability condition.

2. The method according to claim 1, characterized in that The step of obtaining gas parameters of at least one preset gas detection point of a low-pressure EGR system of a vehicle, and calculating the amount of liquid water in the low-pressure EGR system based on the gas parameters, comprises: Collecting fresh air parameters of a first preset gas detection point, and calculating a first water content in the fresh air based on the fresh air parameters, wherein the first preset gas detection point is arranged on an intake manifold of the low-pressure EGR system; Collecting EGR gas parameters of a second preset gas detection point, and calculating a second water content in the EGR based on the EGR gas parameters, wherein the second preset gas detection point is set on the EGR pipe before the EGR valve; Collecting gas parameters at the intercooler outlet of a third preset gas detection point, and calculating the saturated water content at the intercooler outlet based on the gas parameters at the intercooler outlet, wherein the third preset gas detection point is set after the intercooler; The liquid water amount is calculated based on the first water content, the second water content, and the saturated water content.

3. The method according to claim 2, characterized in that The determining the engine operating condition of the vehicle based on the current driving parameter and the gas parameter comprises: obtaining an engine speed of the vehicle based on the current driving parameter; The engine operating condition is obtained by combining the engine speed and the gas mass flow rate in the fresh air parameter.

4. The method according to claim 1, characterized in that: The determining whether the vehicle satisfies a preset combustion stability condition based on the liquid water amount and the engine operating condition includes: Using a preset working condition-water volume comparison table to match the maximum tolerable liquid water volume under the engine working condition; Determining whether the liquid volume is less than or equal to the maximum tolerable liquid volume; If the liquid water amount is less than or equal to the maximum tolerable liquid water amount, it is determined that the vehicle satisfies the preset combustion stabilization condition; otherwise, it is determined that the vehicle does not satisfy the preset combustion stabilization condition.

5. The method according to claim 1, characterized in that Also includes: Recording the number of times the EGR valve is adjusted; When the number of adjustments reaches a preset number, a corresponding low-pressure EGR system historical control message is generated based on the corresponding gas parameters, liquid water volume and engine operating conditions during each adjustment, and the low-pressure EGR system historical control message is sent to the preset terminal.

6. A control device for a low-pressure EGR system, characterized in that: include: A first acquisition module, configured to acquire gas parameters of at least one preset gas detection point of a low-pressure EGR system of a vehicle, and calculate the liquid water volume of the low-pressure EGR system based on the gas parameters; a second acquisition module, configured to acquire current driving parameters of the vehicle, and determine an engine operating condition of the vehicle based on the current driving parameters and the gas parameters; A control module is used to determine whether the vehicle meets a preset combustion stability condition based on the liquid water amount and the engine operating condition, and when the vehicle does not meet the combustion stability condition, determine a target opening of an EGR valve in the low-pressure EGR system based on the liquid water amount and the engine operating condition, and control the EGR valve to open to the target opening to meet the combustion stability condition.

7. The device according to claim 6, characterized in that The first acquisition module includes: a first collection unit, configured to collect fresh air parameters of a first preset gas detection point, and calculate a first water content in the fresh air based on the fresh air parameters, wherein the first preset gas detection point is arranged on an intake manifold of the low-pressure EGR system; a second collection unit, configured to collect EGR gas parameters of a second preset gas detection point, and calculate a second water content in the EGR based on the EGR gas parameters, wherein the second preset gas detection point is arranged on the EGR pipe before the EGR valve; A third collection unit is used to collect gas parameters at the outlet of the intercooler at a third preset gas detection point, and calculate the saturated water content at the outlet of the intercooler based on the gas parameters at the outlet of the intercooler, wherein the third preset gas detection point is set after the intercooler; A calculation unit is used to calculate the liquid water amount based on the first water content, the second water content and the saturated water content.

8. The device according to claim 6, characterized in that The control module comprises: A matching unit, used for matching the maximum tolerable liquid water volume under the engine operating condition by using a preset operating condition-water volume comparison table; A judging unit, used for judging whether the liquid volume is less than or equal to the maximum tolerable liquid volume; A determination unit is used to determine that the vehicle meets the preset combustion stability condition when the liquid water amount is less than or equal to the maximum tolerable liquid water amount, and otherwise, determine that the vehicle does not meet the preset combustion stability condition.

9. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method of the low-pressure EGR system as described in any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the control method of the low-pressure EGR system as described in any one of claims 1 to 5.

Images